16 ALASKAN GLACIER STUDIES The Can-well and Castner Glaciers were seen and mapped by Mendenhall and Glenn in 1898,1 and briefly visited by the authors of this book in 1911. Those to the east were mapped and described by Mendenhall and Gerdine in 1902.2 West of the Canwell and Castner Glaciers, which terminate in the valley of Delta River, are a number of large ice tongues near Mt. Hayes. They have been mapped by the U. S. Geological Survey. Those on the southern side of the Alaska Range have been briefly described by Moffit8 and those on the northern side by Capps.4 Glaciers of the Mt. McKinley Region. This portion of the Alaska Range, between Mt. Hayes and Lake Clark, averages 7000 to lOjOOO feet throughout its length and rises to 17,000 in Mt. Foraker and 20,300 feet in Mt. McKinley, the latter being the highest peak in North America. The east end, near Mt. Hayes, is largely unexplored; the west end has only small glaciers; but the central portion, near Mt. McKinley, supports some large valley glaciers. Those on the southeast slope are larger than those on the northwest. The ice tongues on the northwest include the Herron, Rearburn, Shainwald, Peters, Muldrow, and Harvey Glaciers. On the southeast side are the Pidele, Ruth, Kahiltna, Tokichitna, Caldwell, Fleishmann, Hayes, Stoney, and many unnamed glaciers. Several of these glaciers on the south are 30 or 40 miles long. These glaciers have been observed and mapped by Dickey in 1897, Eldridge, Muldrow, and Spurr in 1898, Herron in 1899, Brooks in 1902, Cook and Dunn in 1903, Cook, Parker, and Porter in 1906.6 All have been retreating so far as observed. Several were utilized as highways by Dunn and Parker in their unsuccessful attempts to climb Mt. McKinley in 1903 and 1906, as well as by Parker and Brown, and by Stuck in their successful ascents of the mountain in 1913 and 1913. ALASKA PENINSULA AND ALEUTIAN ISLANDS Glaciers of the Chigmit Mountains. These low mountains, 2000 to 5000 feet, have large glaciers practically only Where volcanoes rise to a sufficient height to have snoW-fields. Of these active volcanoes Mts. Redoubt and Ilianma, 11,000 and 12,000 feet i MendenhalL W. C., 20th Ann. Kept, U. S. Geol. Survey, Part VII, 1901, pp. 327-828, 330-381, and Map 16; also photograph, Nat. Geog. Mag., Vol. XX, 1909, p. 616. Glenn, E. F., War Dept., Adj. Gen. office, No. XXV, 1899, pp. 1-72 and map. • Professional Paper 15, U. S. Geol. Survey, 1903, p. 58 and PL IX; Professional Paper 41, 1905, pp. 89-90, and map, PI. XTX. • Moffit, F. H.. Bull. 498, U. S. Geol. Survey, 1912, pp. 89-45, 51-58, and PI. I. «Capps, S. R., Bull. 501, U. S. Geol. Survey, 1912, pp. 34-41, and PI. I, Journ. Geol., Vol. XX, 1912, pp. 428-430, 432-3. • Dickey, W. A., Nat. Geog. Mag., Vol. VHI, 1897, pp. 322-327. Eldridge, G. H., 20th Ann. Kept., U. S. Geol. Survey, Part VH, 1900, p. 8, and Map No. 3. Muldrow, E., Nat. Geog. Mag., Vol. XH, 1901, pp. 812-313. Spun, J. E., 20th Ann. Eept, U. S. Geol. Survey, Part VH 1900, pp. 252-258, and Maps 6 and 12. Herron, J. S., War Dept., Adj. Gen. Office, No. xxxi, jgoi, pp. 30, 49, and map. Brooks, A. H., Science, N. S., VoL XVI, 1902, pp. 985-S86; Nat. Geog. Mag., Vol. XIV, 1903, pp. 30-85; Smithsonian Rept. for 1903, pp. 407-425; Professional Paper 46, U. S. Geol. Survey, 1906, map, PI. XI; Prof. Paper 70, U. S. Geol. Survey, 1911, pp. 125-128, 134-136. Dunn, Robert, The Shameless Diary of an Explorer, New York, 1907, two maps. Parker, H. C., Review of Reviews, Vol. XXXV, 1907, pp. 49-58. Porter, R. W., Reconnaissance Map of the Region South of Mt. McKinley, including the Yentna Mining District, U. S. Geol. Survey, 1910. Capps, S. R., Bull. 584, U. S. Geol. Survey, 1913, pp. 36-45 and PI. IE.